transmitting electrical signals



3 sheetsshea 2.

(No Model.)

G. MARCONI.' TRANSMITTING ELECTRICAL SIGNALS.

No. 586,193. Patented July 13, 1897.'

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Zik/ama (No Model.) 3 Sheets- Sheet 8.

Gr. M A R C 0 NI.

TBANSMITTING ELECTRICAL SIGNALS. 110.586,19). Patented July 13, 1897.

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. lS-l Wsses Invenr UNITEDv STATES PATENT OFFICE.

GUGLIELMO MARCONI, or I. ONDON, NGLAND. f

TRANSMITTING ELECTRICAL SIGNALS.l 'v

SPECIFICATION forming* part of Letters Patent No. 586,193, dated July13, 1897.

Application filed December 7, 1896. Serial No. 614.838. (No model.)

Zi) (all whom it may concern:

Bc it known that I, GUoLIELMo MARCONI, student, a subject of the King ofItaly, residing at 2l Burlington Road, London, in the county ot'Middlesex, England, have invented certain new and useful Improvements in'lransmitting Electrical lmpulsesian d Signals and in ApparatusTherefor, of which the` following is a specification.

According to this invention electrical signals, actions, ormanifestations are transmitted through theair, earth, or water by means'pensed with.

of oscillations of high frequency, such as have been called the llertzrays7 or Hertz .oscillations. Usually all line-wires are dis- At thetransmitting-station I employ a Ruhmkorif coil, having in its primarycircuit a Morse key Or other signaling instrument andiat its polesappliances for producing the desired oscillations. f The Ruhm-l kor coilmay, however, be replaced by any other source of high tensionelectricity. wWhen Working with large amounts of energy, it is, however,better to keep the coil or transformer constantly Working for the time.during which one is transmitting, and instead of interrupting thecurrent of the primary interrupting the discharge of the secondary.Inthis case the contacts of the key should be immersed in'oil, asotherwise, owing to the length of the spark, the current Willcoutinue topass after the 'contacts have been separated. At the receiving-'stationlthere isI a local-battery circuit, containing any ordinary receivinginstrument and an appliance for closing the circuit, the latter beingactuated by the oscillations from the transmitting-station.` Whentransmitting throughA the air and it is desired that the signal shouldonly be sent in one direction, I place the oscillation-producer at thetransmitting-station in thc focus or focal line of a reiiector directedto the receiving-station, and I place thecircuit-closer at thereceiving-station in a simi-` lav.` reflector directed toward thetransmittingstation. f When transmitting signals through the earth, Iconnect one end of they oscillation-producer and one end ofv thecircuit-k closer to earth and theaother ends to similar plates,preferably elcctrically'tuned with each other inthe air and insulatedfrom earth.

Figure 1 is a diagrammatic front elevation of the instruments at thetransmitting-station when signaling through the air, Aand Fig. 2 is avertical section of the transmitter. Fig. 2 is a longitudinal section ofthe oscillator to a larger scale. Fig. 3 shows a 'detail on a largerscale. Fig. 4 is a diagrammatic `front elevation of the instruments atthe receivingstation. Fig. 5 is a full-sized view of the receiver. Fig.6 shows a modification of the tubej. Fig. 7 shows the detector. afull-sized View of the liquid-resistance. Figs. 9 and lO showmodifications of the arrangements at the transmitting-station. Fig. lIlshows a modification of the arrangements at the receiving-station.

Referring now to Fig. l, ois a battery, and b an ordinary Morse keyclosing the circuit through the primary of a ltuhmkorll' coil c. Theterminals c of the secondary circuit of the coil are connected to twometallic balls d d, fixed by heat or Otherwise at the ends of tubes (ZV,d', Fig. 2, of insulating material, such as ebonite or vulcanite. c eare similar balls fixed in'the other ends of the tubes d. The tubes diit tightly in a similar tube d2, having covers d3, through which passrods di, connecting the balls d to the conductors. One (or both) of thevrods d4 is connected to the ball d by a ball-and-socket joint and has ascrew-thread upon it working in a nut iu the cover d3. By turning therod therefore the distance of the balls c apart can be adjusted. d5 areholes in the tube (Z2, through Which vascline,'oil, or like material isintroduced into the space between the balls e rig. c is The balls d andc are preferably of solid l brass or copper, and the distance theyshould be apart depends on the quantity and electromotive force of theelectricity employed, the effect increasing With the distance so long asthe discharge passes freely. With a coil giving an ordinary eight-inchspark the distance between c and c should be from one twenty-fifth toOne-thirtieth of an inch and the distance between d and e about one anda half inches. fis a cylindrical parabolic reflector vmade by bending ametallic sheet,

`preferably ofV brass or copper, to form and ixing it to metallic orwooden ribs f. Other conditions being equal the larger the balls thegreateris the distance at W'hich it is possible to communicate. rI havegenerally used s scales I balls of solid brass of four inches diameter,giving oscillations of ten inches length of wave. y

The reflectors applied to the receiver and transmitter ought to bepreferably in length and opening the double at least of the length ofwave emitted from the oscillator. o.

If a very powerful source of electricity giving a very long spark beemployed, it is preferable to divide thespark gap between the centralballs of the oscillator into several smaller gaps in series. This may bedone by introducing between the big balls smaller ones, (of about halfan inch diameter,) hel in position by ebonite frames.

I find that the regularity and power of the discharge of an ordinaryRuhmkori coil with a trembler-break on itsprimary. is greatly improvedby causing one of the contacts of the vibrating break to revolverapidly. I do this by having a revolnble central' core 02, Fig. 3, inthe ordinary screw c?, which is in communication with the platinumcontacts. I cause the said central core with one of the platinumcontacts attached toit to revolve by connecting itV to a small electricmotor c4. This motor can be worked by the same circuit that worksthecoil, or,` if necessary, by a separate circuit. The connectionsare notshown in the drawings. By this means the platinums are kept smooth andany tendency to stick is removed. They last also much longer. At thereceiving-station is a battery whose circuit includes an ordinarytelegraphic instrument (or it may be a relay or other apparatus which itis desired to work from a distance) and a circuit-closer.

In Fig. 4, g'is the battery, and h a telegraphicinstrument on thederived circuit of' a relay n. i

The appliance I employ as a circuit-closer is shown full size at Fig. 5and consist-sof a glass tube g', containing metallic powder or grains ofmetal j', each end of the column of powder being connected to a metallicplate k of suitable length to cause the system to reso,- nateelectrically in unison with the electrical oscillations transmitted. Theglass tube may be replaced in some cases by'one of guttapercha or likematerial. Two shortpieces of thick silver wirej2 of the same diameter asthe internal diameter of the Itubej, so `as to .fit tightly in it, arejoined to two pieces of platinum wire ja.' The `tube is closed `andsealedonto the platinum wiresjs at both ends.

Many metals can be employed for producing the powder or filings j; but Ipre'fer to use a mixture of two or-'more diierent metals.

I find hard nickel tobe ,the best metal, and I pre-fer to add to thenickel filings about t-en per cent. of hard-silver lin gs, whichAincrease greatly the sensitiveness of the tube to electricoscillations.By increasing the proport-1on of silver powder or grains thesensitiveness of the tube also increases; but it is bet ter for ordinarywork not to have a tube of too great sensit-iveness, as it might beindu-- 'tity as to clot or cake the lings.

the filings and mixing up untiltheme'rcury is absorbed.

The mercury must not be in such la'quan- An almost imperceptible globuleis suiicient for a tube. Instead of mixing the mercury withthe powderone can obtain the same effects by slightly yamalgamating the innersurfaces of the plugs which are to be in contact with the filings. Yerylittle mercury must be used, just sutilcient to brighten the surface ofthe metallic plugs without showing anyffree globules. The

size of the tube and the distance between the two metallic stopsmay-vary under certain following size: The tube 7' is one and one-halfinches long and one-tenth or one-twelfth oi' an inch internal diameter.The length of the stops b7'2 is about one-fifth of an inch, and thedistance between the stops is about one-thirtieth of an inch. I nd thatthe smaller the space between the stops in the tube the more sensitiveit proves, but the space cannot under ordinary circumstances beexcessively shortened withoutinjuringthe vfidelity of the transmission.

The metallic powders ought not to be fine, but rather as coarse as canbe produced by a large and rough file.

All the very ne powder ought to be removedl by blowing r sifting.

The powder ought not to be compressed be-` tween the stops, but ratherloose and in such a condition that when the tube is tapped the powdermay be seen to move;

The tube must be sealed, but a vacuum inside it is not essential, exceptthe slight vacuum which results from having heated it while sealingit.Care must alsobe taken not to heat the tube too much inthe center whensealing it, as it would oxidize the surfaces of the silf ver stops andalso the powder, which would diminish its sensitiveness. I usev insealing the tubes a hydrogen and air flame. A vacn'nm is, however,desirable, and I have .used one of about one-one-thousandth of anatmosphere, obtained bya mercury-pump. It is also IOS necessary for thepowder or-grains to be dry and free from grease or dirt, and the filesused in producing the same ought to be frequently I washed and dried andused when warm.

If the tube has been well made, it should be sensitive to the inductionof an ordinary elecmilliampere to flow through itwhen active.

If a stronger'current is necessary, several tubes maybe put inderivation between the c quite as satisfactory as the single tube.

tuned plates, but this arrangement is not It is necessary when usingtubes ofthe type I have described not to insert in the circuit more thanone cell of theLeclanch type, as a higher electromotive force than 1.5volts is apt to pass `a current through the tube even when nooscillations are transmitted. I can, however, construct tubes capable ofworking with y there are several spaces-separated by sections of tigilt-fitting silver wire. A tube thus constructed, observingclalso therulesof construc-v tion of my tubes in general, willwork satisfactorilyif the electromotiveforce of the battery in circuit with the tube isequal to 1.2

' yolts in nltiplied by the number of gaps. With this tube also it iswell not to allow a current of more than one milliampere to pass.

' The tube j may be replaced by other forms of imperfect electricalcontacts,'but this is not desirable. i

rllhe plates'c are of copper or aluminium or other metal, about half aninch or more' broad,

. about one-iiftieth of an inch thick, and preferably of such a lengthas to be electrically tuned with the electricoscillat-ions transmitted.The meansl I adopt for fixing the length of the plates is as follows: Istick a rectangular strip of tinsfoil m (see Fig. 7) about twenty incheslong (the length depends on` the supposed length of'wave that one ismeasuring) bymeans of a weak solution of gum ontof a glass plate m. Thenby means of avery sharp lpenknife or point I cut across the middle ofthe tin-foil, leaving a mark of division If this detector is heldin theproximity (four or live yards) and parallelwith the axis of theoscillator in action, it will show little sparks at m2. It' the lengthof the pieces of tin-foil approximatesto the length of wave emitted fromthe oscillator, the spark will take place rbetween them at a certaindistance from the transmitter, which is a maximum when they are ofsuitable length. By shortening or lengthening the strips, therefore, itis easy to find the length most appropriate to the length of waveemitted by the oscillator. It is desirable to try this detector in thefocus or focal line of the reflector. The length so found is the properlength for'the plates k, or rather these should be about half an inchshorter'on account of the .length oi' the sensitive tube .7',

' connected between them.

Z is a cylindrical parabolic reflector similar to that used at thetransmitting-station.

'lhe plates la may be in the form of tubes or even wires. y

It is slightly advantageous for the focal distance of the reflector to'be equal to one-fourth .or--threefourths of the wave length of the 0s-:transmitting-station, the 'tube j does not conduct the currentfand thelocal-battery circuit p is broken, but when the powder or tube isinfluenced by the electrical oscillations from the transmitter itconducts and closes the circuit. I ind, however, that when once lstartedthe powder in the tube continues to conduct even when the oscillationsfrom the transmitter have ceased, but if it be shaken ;or tapped thecircuit is broken. A tube well prepared will instantly interrupt thecurrent passing through it at the slightest tap, provided it is insertedin a circuit in which there is little self-induction and smallelectrombtiv'e force, such as a single cell, and where `the effects ofself-induction have been removed by one of the methods which I willpresently describe.

The two plates 7o communicate with the lo cal circuit through two verysmall coils k',

which I will call choking-coils, formed by winding a few inches 'ofverythin and insulated copper wire around a bit of iron wire about an inchand a half long. The object of these chohin g-coi-ls is to prevent thehigh-frequency oscillation induced across these plates bythe transmitterfrom dissipating itself by running along the local battery wires whichmight weaken its effect on the sensitivetube j. These choking-coilsmay,however,be sometimes Areplaced. bysimple thin wires. They may alsobe connecteddirectly to the tube j. 'The local circuit in which thesensitive tube j is inserted contains a sensitive relay n, prefs erablywound to a resistance of about twelve hundred ohms. This resistance neednot be necessarily that ofthe relaybut may be the sum of the resistanceof the relay and another additional resistance. The relay ought to beone possessing small self-induction- The plates k, tube j, and coils loare fastened by means of wire stitches o to a thin glass tube o,preferably not longer than twelve inches, firmly fixed at one end to astrong piece of timber o2. .This may be done by means of lwood orebonite grasping-screws.

I do the tapping automaticallyby the current started by the tube,employing a trembler 10 on the circuit of the relay fn similar inconstruction to that of an electric bell, but havling a shorter arm. TheAvibrator must be carefully adjusted. Preferably the blows shouldbedirected slightly upward to prevent In place of the filings from gettingcaked. tapping the tube the powder can be disturbed by slightly movingoutward and inward one or bothY of the stops ,7"2, the trembler p beingreplaced by a-small electromagnet (or magnets) whose armature isconnected to the stop.

I ordinarily work the telegraphic receiver h (or other instruments) by aderivation, as shown, from the circuit which works thc trembler p. Theylcan also, however, be worked in series with the trembler. "When workingordinary sounders or Morse apparatus, a special adjustment of thc sameis sometimes needed to enable one to obtain dots and dashes. Sometimesit is necessary to work the telegraphic instruments or relays from theback-stops of the first relay, as is done in IIC;

' some systems of multiple telegraphy. ,Such

adjustments are known to telegraphic experts.

Bymeans of a tube with multiple gaps it is 'possible to work thetrembler and also the` signaling or other apparatus direct onA theeircuit which contains the tube, but I prefer -when possible towork`with the single-gap tube and the relay, as shown. With a sensitive andwell-constructed trembler it is also `'possible to work the trembler'with the singlegap tube in series with it without the relay. Inderivation on the terminals of the relay 'n is placed an ordinaryplatinoid resistance double-wound' (or wound on the bight, as it is-.sometimes termed) coil q of aboutl four times'the resistance of therelay, which prevents the self-induction of the windingof the relay fromaeetin g the sensitive tube.

The circuit actuated by the relay contains an ordinary "battery q" of'about twelve cells ratus, if on a derivation, lshould have aresistanceequal to the resistance of the trem- .bler p. A platinoidresistance h of abeht ive times the resistance of the instrumet isinserted in .derivation across the terminals of the Ainstrument andconnected as close to the same as possible. In derivation a ross .-,lthe

terminals of the trembler pis placed another.v

platinoid resistance also of about five times* the resista-nce of thetrembler. 'A similar re- `sistanee p2 is inserted'in a circuitconnecting -the vibrating contacts of., the trembler!y In derivationacross the terminals of the relaycircuit it is well to have a liquidresist-ance s, which is constituted of a series of tubes, 'one of whichis shown full size in Fig. 8, filled with Water acidulated with sulfuricacid. I /The l number othese tubes in series across lthe said terminalsought to be about ten for a circuit of fifteen volts, so as to prevent,in con-. sequence of their counter electromotive force,

= the current of the local battery fro'mpassing through them, butallowing the high-tension jerk of current generated at the opening ofthe circuit in the relay to pass smoothly across them without producingperturbing sparks at' the 'movable contact of the relay. It is alsonecessary to insert a platinoid resistance in derivation'on .anyapparatus one may be working on the local circuits. These resistanesought also to be insertedin derivation on the terminals of anyresistance which may l be apt to give self-induction.

I have hitherto only mentioned the use of cylindrical reflectors, but itis also `possible ,to use ordinary concavereilectors, preferablyparabolic, such as are used for projectors.-

It is not essential to have a reflector at the transmitters andreceivers, but in their absence the distance at which one cancommunicate is much smaller. y 'I iind it convenient when transmittingacross longdistances to make mitter shown in Fig. 9. Y X. t t are twopoles connected by a rope t', to which are suspended by means ofinsulating Suspenders two-metallic plates i? t2, preferably in the formof cylinders closed at the top, connected to the spheres e (inoil'orother dielectric, as before) and to the other balls t3 in proximgity tothe spheres c', in com mu nicationwith the coil or transformer c., Theballs t3 are not 'absolutely necessary, as the plates t2 may be -made tocommunicate with the coil or transformer by means of thin insulatedwires. The receiver I adopt with this transmit-ter is simiuse of thetrans.l

lar Ato it, except that the spheres ev are replaced by the sensitivetube j and plates 7.', while the spheres t3 are replaced by thechoking-coils k', in communieationwith the loc`al circuit. It may beobserved that, other conditions being equal, the larger the plates atthe transmitter and receiver and the higher 4 they are from earth and.to a ccrtainextent the farther 'apart they are the greater is thedistance at which correspondence is possible.

When transmitting through the earth or water, I use a transmitter asshown in Fig. 10. lI connect one of the spheres d to earth E, preferablylby a thick Wire, and the other lOO to a plate oreonduotor u, suspendedon a pole 4 o and insulated from' earth; or the spheres (l ,may b eomitted and one of the. spheres e be connected to earth and the othertothe plate or conductora. At the receiving-stationl1`ig. 1 l, I connectone terminal of the sensitive tube ,j to earth E, also bya thick wire,and the other to a plate or conductor w, preferably similar to u. rIheplate w may be lsuspended on a pele a: and must be insulated from earth.The largerv the plates of the receiver and transmitter and the higherfrom the earth the plates are suspended the greater is the distance atwhich it is possible -to'communicate When' using, the last-describedapparatus, it is not necessary to have the two instruments in view ofeach other, as it -is of no consequence if they are separated bymountains or other obstacles; At the receiver it is possible to pick upthe oscillations vfrom. the earth or water without having the plate w.This may be done by connecting .the terminals of the sensitive'tube j totwo earths, preferably at a certain distance from each, other and in aline with the direction'from which the oscillations .are coming. Theseconnections must not be entirely conductive, but must contain acondenser of suitable capacity-say one square yardof,surface.` Balloonscan also be used instead of plates on poles, provided they carry upaplate or are themselves made conductive by being coveredwith tin-foil.Asthe height to which they may be sent is great,l the distance at whichcommunication is possible be- IIO lio

comes greatly multiplied. Kites may also be successfully employed ifmade conductive by means of tin-foil.

The apparatus above described is so sensitive that it is essentialeither that the transmitters and receivers at each station should be ata considerable distance from eachother or that they should be screenedfrom each other by stout metal plates. It is sufficient to have all the'telegraphic apparatus in a metal box and any exposed part of the circuitof the receiver inclosed in metallic tubes which are in electricalAcommunication with the box. (Of course the part of the apparatus whichhas to receive the radiation from the distant station must not beinclosed, but possibly screened from the local transmitter by means `ofmetallic sheets.) Vhen working through the earth or water, the localreceiver must be switched out of circuit when the transmitter is atwork, and this may also be tact, choking-coils connected to thecontact,`

a circuit through the coils, and contact and means actuated by thecircuit for'shaking the contact.

4. In a receiver for electrical oscillations the combination of a tubecontaining metallic powder, a circuit through the powder and meansactuated by the circuit for shaking the powder.

5. In a receiver for electrical oscillations the combination of a tubecontaining metallic owder, metallic plates connected to the powger, acircuit through the powder and means actuated .by the circuit forshaking the powder. c l

6. In a receiver for electrical oscillations the combination of a tubecontaining metallic powder, metallic plates connected to the powder,choking-coils connected to the powder, a circuit through the coils andpowder and means actuated by the circuit for shaking the powder.

7.- lu a receiver for electrical oscillations the combination of a tubecontaining a mixture of metallic powders, a circuit through the powder,and means actuated by the circuit for shaking the powder.

S. In a receiver for electrical oscillations the combination of a tubecontaining a mixture of metallic powders, metallic plates connected tothe powder, a circuit through the powder and means actuated by thecircuit for shaking the powder. V

9. In a-reeeiver for electrical oscillations the combination of a tubecontaining a mixnectcd to thel powder, choking coils connected to thepowder, a circuit through the coils, and powder and means actuated bythe circuit'for shaking the powder.

l0. In a receiver for electrical oscillations the combination of a tubecontaining a mixture of metallic powder and mercury, a circuit throughthe powder and means actuated bythe circuit for shaking the powder.

11. In a receiver for electrical oscillations theV combination of a tubecontaining a mixtureof metallic powder and meren r f, metallic plates.connected to the. powder, a .circuit through the powder and meansactuated by.

means actuated by thc circuit for shaking the powder.

14. In a receiver for electrical oscillations the combination of a tube,metallic plugs in 'the tube,'metallic powder between the plugs,

metallic plates connected to them, a circuit through the plugs andpowder .and means actuated by the circuit for shaking the powder.

15. In a receiver for electrical oscillations the combination of atube,metal'lic plugs in the tube, metallic powder between the plugs,metallic plates connected to the plugs, clickingcoils connected to theyplu gs, a circuit through the coils and plugs and means actuated by thecircuit'forgshaking the powder.

16. ,In a receiver for electrical oscillations the combination of atube, metallic plugs in the tube, a mixture.ofjmetallic powders betweenthe plugs, a-"circuit through the plugs and powder and mea cuit forshaking the powder.

17. In a receiver'fo'r-electrical oscillations the combination of atube, metallic plugs inV ,s actuated by the cir`- `ture of metallicpowders,`metallic plates con- IOO 18. In a receiver for electricaloscillations the combination of a tube, metallic plugs in the tube, amixture of .metallic powders between tlic plugs, metallic platesconnected to the plugs, choking-coils connected to the plugs, a'circ'uitthrough the coils plugs and powder and means actuated by the circuit forshaking/the powder. l Y

19. In a receiver for electrical oscillations the combination of a tube,metallic plugs in the tube, a mixture of metallic powder and mercurybetween the plugs, a circuit through the plugs and powder and meansactuated by the circuit for shaking the powder.

20. In a receiver for electrical oscillations the combination of a tube,metallic plugs in the tube, a mixture of metallic powder and mercurybetween the plugs, metallicv plates connected to the plugs, acircuitthrough the plugs and powder and means actuated by the circuit forshaking the powder.

2l. 4In a receiver for electrical oscillations the combination of atube, metallic plugs in the tube, a mixture of metallic powder andmercury between the plugs, metallic plates connected to the plugs,choking-coils connected to the plugs, a circuit through the coils plugsand powder and means actuated bythe circuit for shaking the powdeny 22.In a receiver for electrical oscillations the combination of animperfect velectrical contact, a circuit through thecontact, a relayactuated by lthe circuit and means actuated by the relay for shaking thecontact,

f 23. In a receiver for electrical oscillations the combination of animperfect electrical contact, metallic plates connected to it, a circuitthrough the contact, a relayactuated by the circuit and means actuatedbythe relay for shaking the cont-act.

24. In a receiver for electrical oscillations the combination of animperfect electrical,

contact, metallic plates connected to the contact, choking-coilsconnected to the contact, -a circuit through the coils and contact, arelay actuated by the circuit and means actuated bythe relay for shakingthe contact.

- 25. In a'receiver for electrical oscillations the combination of atube containing metallic powder, a circuit through the powder, a

relay actuated by the circuit and. means ac-4 tuated by the relay forshaking the powder. 26. In a receiver for electrical oscillations thecombination of a tube containing metallic powder, metallic platesconnected to thel powder, a circuit through the powder, a relay actuatedbythe circui-tand means actuated by the relay for shaking .the powder..i

27. In a receiver for electrical oscillations the combination of a tubercontaining metallic powder, metallic plates connected to the powder,choking-coils connected to the powder a circuit through the coils andpowder a relay actuated by the circuit and means actuated by the relayfor shaking the powder.

28. In a receiver for electrical oscillations the combination of atubecontaining a mixture of metallic powders, a circuit through .the powder,a relay actuated by the circuit and means actuated by the relay forshaking 'the powder.

29. In a receiver for electricalfoscillations the combination of a tubecontaining a mixe ture of metallic powders, metallic plates connected tothe powder, a circuit through the powder, a relay actuated by thecircuit and means actuated by powder. y

30. Inra receiver for electrical oscillations the combination of a tubecontaining a mix ture ofmetallic powders, metallic plates connected tothe'powder, choking-coilsconnected to the powder, a circuit through thecoils and powder, a relay actuated by the circuit and means actuated bythe relay for shaking the powder. p

3l. In a receiver for electrical oscillations the combination of a tubecontaining a mixthe relay for shaking the s ture of metallic powder andmercury, a circuit through the powder, a relay actuated by thefcircuitand means actuated by the relay for shaking the powder.

' 32. In a receiver for electrical oscillations the combination of altube containing a mixture of metallic powder and mercury, metallicplates connected to thepowder, a circuit through the powder, a relayactuated by the circuit and means actuated bythe relay for shaking thepowder.

y 33. In a receiver for electrical oscillations the combination of atube containing a mixture of metallic powder and mercury, metallicVplates connected to the powder, choking-coils connected to the powder, acircuit through the coils vand powder, a relay actuated bythe circuitand means actuated by the relay for shaking the powder.

34. In a receiver for electrical oscillations the combination of a tube,metallic plugs-in the tube, metallic powder betweeny the plugs, a.circuit through-the plugs and powder, a re- `lay actuated .by thecircuit and means actu- -ated yby the relay for shaking the powder.

85. In a receiver for electrical oscillations thecombination of a tube,metallic plugs in the tube, metallic powder between the plugs, metallicplates connected to the plugs, a circuit through the, plugs and powder,a relay actuated by the circuit and means actuated by the'relay forshaking the powder.

36. In a receiver for electrical oscillationsl the combination of atube, metallic plugs in the tube, metalliclpowder between the plugs,metallic plates connected to the plugs, choking-coils connected to thelplugs, a 'circuit through the coils, plugs and powder, a relay actuatedby the circuit, and means actuated by the relay for shaking the powder.

37. In a receiver for electrical oscillations the combination ofa-tu'be, metallic plugs in the tube, a mixture of metallic powdersbetween the plugs, a circuit through the plugs and powder, a relayactuated by the circuit, and means actuated by the relay for/shaking thepowder.

38. In a receiver -for electrical oscillations.

tween the plugs, metallic plates connected to loo' ' the plugs,a circuitthrough the plugs and' powder, a vrelay actuated bythe circuit, andmeans actuated by the relay for shaking the powder.

39. In a `receiver for electrical oscillations the combination of atube, metallic plugs in the tube, a mixture of metallic `powders betweenthe plugs, metallic plates connected to the plugs, choking coilsconnected to the plugs, a circuit through the coils, plugs vand powder,a relay actuated by the circuit and means actuated by the relay forshaking the powder.`

40. In a receiver for electrical oscillations the combination of a tube,metallic plugs in the tube, a mixture of metallic powder and mercurybetween the plugs, a circuit through the plugs and powder, arelay-'actuated by the circuit and means actuated by the relay forshaking the powder.

4l. ln a receiver for electrical oscillations the combination of a tube,metallic plugs in the tube, a mixture of metallic powder and mercurybetween the plugs, metallic plates connected to the plugs, a circuitthrough the plugs and powder, anelay actuated by the circuit and meansactuated bythe relay for shaking the powder.

42. In a receiver for electrical oscillations the combination of a tube,metallic plugs in the tube, a mixture of metallic powder and mercurybetween the plugs, metallic plates connected to the plugs, choking-coilsconnected to the plugs, a circuit through the coils,

plugs and powder, a relay actuated by the circ uit and means actuated bythe relay for shak.

ing the powder.

48. The combination ot a spark-producer at the transmitting-station, anearth connection to one end of the spark-producer, an insulatedconductor connected to the other end, an imperfect electrical con'tactat the receiving-station, an earth connection to one end of the contactan insulated conductor connected to the other end and a circuit throughthe contact.

44C. The combination lof aspark-producer at the transmitting-station, anearth cunnection to one end of the spark-producer, an insulatedconductor connected to the other end, an imperfect electrical contact atthe receiv in g-station, an earth connection to one end of the contactan insulated conductor connected to the other end, a circuit through thecontact and means actuated by the circuit for shaking the contact.

The combination of a spark-producer at the transmitting-station, anearth Iconnec tion to oneend of the sparkLproducer, an insulatedconductor connected to the other end, an imperfect electrical'contact atthe receiving-station, choking-coils connected to each end of thecontact, an earth connection to one end of the imperfect contact aninsulated conductor connected to the other end and a circuitthroughthecoils and contact.

4G. The combination of a sparkeproducer at the transmitting-station, anearth connection to one end of the spark-producer, an insulated conductor connectedto the other end, an imperfect electrical contact at thereceiving-station, choking-coils connected to each end of the contact,an earth connection to one sulated conductor connected to the other'end,a tube containing metallic powder at the receiving-station, an earthconnection to one end of the powder, an insulated conductor connected tothe other end and a circuit through the powder. i f

48. The combination of a spark-producer tion to one end of thespark-producer, an insulated conductor connected to the other end, atube containing metallic powder at the receiving-station, an earthconnection to one end of the powder anA insulated conductor connected tothe other end, a circuitthrough the'powder and means actuated by thecircuit for shaking the powder. 49.' The combination of a sparkproducerat the transmittingstation, an earthconnection toone end of thespark-producer, an insulated conductor connected to the other end, atube containing metallic powder at the ,receiving-station, choking-coilsconnected to each end of the powder, an earth connection to one end ofthe powder, anv insulated con'- ,ductor connected to the other end and acircuit through the' coils and powder.

v 50. The combination of a spark-producer at the transmitting-station,an earth connec tion to one end of the spark-producer, an insulatedconductor connected to the other end, a tube containing metallic powderat-the receiving-statio n, choking-coils connected to each end of thepowder, an earth connection to onei end of the powder,'an insulatedconductorconnected to the other end, a circuit through the coils andpowder and means action to one end of the spark-producer, an inat thetransmitting-station, an earth connec- IOO tuated by the circuit forshaking the powder.

5l. The combination of aspark-producer at the transmitting-station, anearth connec! `tion to one end of the spark-producer, an insulatedconductor connected to theother end, a tube containingmetallic powder atthe receiving-station, choking-coils and earth connection throughcondensers connected to each end of the powder, a circuit through thecoils and powder and means actuated by the circuit for shaking thepowder'.

52. ln a receiver for electrical oscillations,

contact, a circuit through the contact, an electric trembler shaking thecontact, and means for preventing the self-induction of the tremblerfrom aiecting the contact.

the combination of an imperfect electrical..

,2 5 be given out bythe receiver.

53. -A receiver for electrical oscillatorykimpulses having a mediumwhose electrical resistance'is altered by the received electricaloscillations, a trembler or` shaker for acting uponthe'variable-resistance medium to re` store itt'to its normal conditionof -electrical resistance,` and means fol-controlling such trembler tocause it to act upon the variable-i resistance medium to restoreit toits normal' condition aftereach reception of such oscillatory impulses.i y y 54. 5A' receiver for electrical oscillatory impulses havinga'medium whose electrical resistance is altered by the/receivedelectrical oscillations, a trembler or shaker for acting upon thevariable-resistance medium toeren store it to 'its .normal condition ofelectrical resistance, means controlling such trembler tocanse it to actupon the variable-resistance 26* medium to restore it 'toitsnormal/condition after veach receptionof such oscillatory im-- pulses,and means for rendering manifest said electrical oscillatory impulsesconsecuf tively received,wliereby defined signals may 55; Thecombination ofa transmittercapaffv trie oscillatory limpulses or rays,and a receiver responsive thereto having a variableresistance mediumwhose resistance is altered by such received oscillatory impulses, meanscontrolled by the receivedoscillations for restoring such medium toitsnormal condition aft-er each reception of such oscillations, and meansforrenderin g manifest the received oscillations, whereby signals sentfrom the transmitter maybe received upon the receiver.

' 56. The combination of a transmitter capable ofproducin g electricaloscillations or rays at thedwill of the operator, and a receiver locatedat a distance and having va conductor tuned to respond to suchoscillations, a variable-resistance#medium, in circuit with theconductor, whose resistance is altered by the received oscillations,means controlled by the received oscillations for restoring theresistance medium;J to its normal condition after each reception of4such oscillations, and means for rendering the received oscillationsmanifest. i

GUGLIELMO MARCONL WILFRED CORPMAEL,

i ble' of. producing at will of the operator lelec,-

v FRED C. HARIES. A

